Stabilized wax emulsion



Patented July 27, 1954 STABILIZED WAX EMULSION Sherwood '1. Cross, Christiana Hundred, Del., as-

signor to Atlas Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application December 12, 1950, Serial No. 200,500

This invention relates to emulsions and emulsifier compositions and more particularly to fluid emulsions of waxes which are solid at ordinary temperatures and emulsifier compositions therefor.

Emulsions of waxes, and emulsifying agents for use in preparing such emulsions are commercially valuable compositions and have been the subject of much investigation. For example, U. S. Patents 2,374,931 and 2,380,166, both granted to W. C. Griffin disclose emulsifiers as well as emulsifiable wax compositions and emulsions utilizing the emulsifiers, which comprise mixtures of lipophilic partial esters and hydrophilic hydroxypolyoxyethylene ethers of such esters. Emulsions of solid waxes prepared in accordance with the teachings of these patents are resistant to hard water, stand dilution well without precipitating wax, and are stable on storage. They have one disadvantage, however, in that certain 14 Claims. (Cl. 252-3115) types of agitation, particularly a reciprocating 1 agitation such as is imparted by a back-and-forth shaking of a vessel partially filled with the emul sion, cause the wax particles to agglomerate into lumps, much as butter is separated from cream in churning. Particularly where concentrated wax emulsions are to be packaged for dilution in home use, as in liquid home laundry wax compositions, is this type of instability objectionable, since it is almost instinctive with the user to shake a bottle containing a creamy emulsion before withdrawing a portion for dilution.

It is an object of this invention to provide an improved emulsifier composition suitable for preparation of fluid emulsions of solidified wax.

A further object is to prepare improved emulsifiable wax compositions.

A still further object is to prepare fluid emulsions of solid Waxes which are stable to the separation of wax agglomerates when subjected to shaking.

The above and other objects of the invention will become more apparent in the course of the following description and in the appended claims.

Compositions which accomplish the above objects in accordance with the present invention comprise the emulsifiers in the above mentioned Grimm patents and contain in addition to the lipophile partial esters and the hydrophile hydroxypolyoxyethylene ethers, a hexitol borate the pH of which has been adjusted to a value between 4.5 and 9.0. Preferably, though not necessarily, the compositions also include a solid long chain fatty acid, which appears to ooact with the hexitol borate in further enhancing the effect of the latter in stabilizing the emulsion against shaking. Within the purview of the invention are emulsifier compositions containing the herein-disclosed stabilizing agents, emulsifiable wax compositions containing the emulsifiers and stabilizers, and emulsions employing the above mentioned emulsifying agents and the herein-disclosed stabilizers.

The following description of the mixed emulsifying agents employed in the stabilized compositions of the present invention is paraphrased from that in the specification of U. S. 2,380,166, mentioned hereinbefore.

For convenience in description the emulsifiers will be described generally as mixtures of type A and type B emulsifiers.

Type A emulsifier comprise lipophilic partial long chain fatty acid esters of polyhydroxylic organic compounds. Type B'emulsifiers include, in general, the highly hydrophilic hydroxypolyoxyethylene ethers of type A compounds.

- The adjective lipophilic is here used to describe compounds which have good oil solubility or dispersibility and little or no water solubility.

" The term highly hydrophilic is descriptive of compounds which are from readily dispersible in to completely miscible with water.

More particularly the type A esters are the esters of water-insoluble fatty acids having at least 12 carbon atoms, such as those obtainable by hydrolysis of natural fats, waxes, and oils, or from oxidation of parafiins, and suitable aliphatic polyhydroxylic compounds. Partial esters of water-insoluble cyclic acids, such as naphthenic acids, are likewise satisfactory type A components of the present emulsifiers. Suitable polyhydroxylic compounds comprise ethylene glycol; diand tri-ethylene glycol; glycerol and polyglycerols; pentaerythritol; pentitols; hexitols and the cyclic inner ethers thereof; cyclitols such as inositol; oligosaccharides such as glucose, sucrose, and lactose; the glycol and lower polyglycol ethers of such polyhydroxylic compounds; and other polyhydric compounds of typical hydrophile char acter.

In these type A partial esters, monoesters tend to be the most effective.

Particularly suitable partial esters are those of the mixed cyclic inner ethers of the hexitols, such as sorbitans and sorbide from sorbitol, or mannitans and mannides from mannitol. For optimum performance, in the said partial esters of cyclic inner ethers the ratio of hydroxyl value to ester value lies between 3 and 1 and preferably between 3 and 1.5.

to 30 oxyethylene groups per mol. The longerthe fatty acid radical in the ester andsthe-higher.

the degree of esterification, the more oxyethylene group required for optimum results.

Methods of preparing thetype A esters and type B ether-esters above described are presentedin detail in aforesaid PatentqiNo. 2,380,166and need not be repeated here.

Likewise, the proportioning of type A and type B components to formemulsifiers for waxes, and emulsions containing waxes is adequately treated in the specification ofsaidmatent; and in the modified compositions of 'thezpresent invention the same rangeof proportion of type 'A to type B'componentsis employed. The propor'- tion may be defined in'termsof' the' ratioof oxyethylene units in the B'fcomponent tm the total number ofester groupsin A' and B-i'v For emulsifying waxes, the said ratio of oxyethylene roups in B'to ester groups in: A :.and'*B?lies between the limits of '1.-5 and"9 The paraffin' waxes in emulsion are particularly susceptible of agglomeration and separating when shaken and it is to emulsifiable paraffin wax compositions, paraflih wax'emulsions, and emulsifiersfor parafiin wax that-th'is' invention is particularly directed. Thesai'd'parafiih'waxes include crude scale wax= as =well as more highly refined'white waxes such as'th'ose used for house hold purposes. Also included are therso-called microcrystalline 'parafii'n waxes which are" available in a number of grades; so far as is khown; the invention is applicable to emulsions-bf' any waxwhich exhibits 'the property of churning out wax agglomerates on 1 shaking.

In'addition to the prionart-components of emulsifiers for waxes, theemulsifiercomposition;

emulsifiable waxes and emuls'ions offiithepresent invention contain from'3'% to"'%"b'y weight, based on the sumof 'th'e weig'hts oftypeA and type B'components, of a partially neutralized hexitol'borate, preferably apartially-neutralized sorbitol borate. sorbitofborates and va'riously neutralized sorbitol b'orates' are the" subject" of U. S. Patent No. 2,223,949 to Bremer. Borates useful in the present inventionare 'sorbito1 mono-' borate dicondensation products in which sufficient of the acidic hydrogen of the resulting condensation product is replaced by' a monovalent cation to result in aborate' ofpI-I between 4.5 and 9. Thus, the products of l lxamples 2, 3, 5' and 6 of the aforementioned patentaresuitable ingredients. Equally satisfactory are sorbitol monoborate compositions which have been condensedto' a lesser degreethan'taught in the above mentioned Bremer patent and neutralized'to the indicated extent. The-preparation of a suitable borate compound'for-the purpose is detailed in the following:

Example I pounds of boric acid; Thexachargezfiwas' heated and agitated until the temperatureaofithe:vigorously boiling charge was 110 C. The contents of the vessel were then cooled to 90 C. and the acidity partially neutralized at that temperature, by the gradual addition of 385 pounds of sodium hydroxide added in the form of 50% aqueous solution. The resulting product has a pH,Tin50% solution, of "7.0. It'wasbutted with water to a concentrationof solidsto yield a viscous pale yellow liquid drying to a resinous, tack free, surface when spread out in a film.

By=varyingthe amount of caustic, the pH of the sorbitol b'orate resulting from the first step of 'Example I could have been controlled to any desired value within the range of 4.5 to 9.0 to "produce 'borates suitable for use in the present invention; Furthermore, instead of caustic soda,-=there might have been employed any other neutralizing agent supplying a monovalent cation such; for example, as potassium hydroxide, ammonia, triethanol amine or the like.

Whileit has been found'that'emulsions containing from*3'%' to 25% of'a partiallyneutialized hexitol monob'orate based 'on-the weight of the 'hereinb'efore disclosed combined emulsifiers, have remarkably increased resistance to the separation of wax 'agglomerates upon shaking, a still further improvement can be effected in this direction by the'incorporation of a solid long chainfatty acid, such for example, as stearic acid'or palmitic acid, and preferred compositions in accordance with the invention contain this ingredient in an' amount -not greater than 2.5 times the weight of the added 'borate compound providing that the sum of the weights of said borate and said'solid fatty acid'shallbe not more than' 60%' of the weight "of "thesum of the type A and'type' B emulsifiers in' the composition. Particularly useful are those compositions containing 2'parts of "stearic acid 'per part of sodium sorbitol borate and from 6to 18% of said borate based'on the sum of" type Aand'type B components in'the emulsifier composition.

Inaddition to" the ingredients named above, the emulsifier compositions of the invention may contain minor amounts'of "othercomponents to render'the ingredients compatible,- to perfume the product, to colorit, or'the like. In particular, asmall amount'ofwater is useful'to properly incorporate the boratecompound with the other ingredients.

Specific compositions illustrating the invention are described in the'following examples.

Example II.

Melt together 27.4 grams of commercial sorbitan monopalmitate (type A component), 34.7 grams of 20-polyoxyethylne sorbitan monopalmitate (type B'component) and 17.1 grams of stearicacid, bringingthe mixture to a temperature of about 60 C. Separately prepare a solution containing 8.3 grams of sodium sorbitol monoborate-pH '7', in TE-grams of water at the same temperature. Add the water solutions to the mixed emulsifier and stearic acid, mix thoroughly and-cool rapidly. The resulting waxy solid is an excellent emulsifier for the preparation of .paraffiniwax'emulsions.

Example II (a) Melt together 40 grams of household paraffin wax and 7.35'grams of the product of Example II, bringing the temperature of the mixture to about 60 C. Add- 5265 grams of water; also at about 60P*C., to'the molten mixture stirring conti-nuously. Allow the-emulsion so formed to cool gram of sodium sorbitol monoborate-pH luted with either soft or hard water to form stable emulsions.

. Example III The following instructions are for the preparationof an emulsifiable wax concentrate in solid form. Melt together 80.5 grams of household parafiin wax, 4.5 grams of commercial sorbitan monopahnitate, 5.7 grams of ,20-polyoxyethylene sorbitan monopalmitate, and 2.8 grams of stearic acid. Separately prepare a solution of 1.4 grams of sodium sorbitol monoborate pH 7 in 5.3 grams of water and add the solution, at a temperature of about 60 C. to the molten wax and emulsifiers at about the same temperature. Upon cooling a solid waxy composition is obtained which may be readily converted to a stable emulsion by melt- ,ing and'stirring in warm water to adjust the concentration as desired.

Example IV Melt together 23.4 grams of paraflin wax, 1.2

grams of commercial sorbitan monopalmitate, 1.8

,grams of -polyoxyethylene sorbitan monopalmitate and 0.8 gram of stearic acid. To the molten mixture at about 60 0., add with continuous stirring a solution of 0.4 gram of sodium sor bitol monoborate-pI-I 5, in 72.4.grams of water. A stable emulsion, very resistant to-wax agglomeration results. Example V very stable. Example VI Substitute ammonium sorbitol monoborate pH 7 for the sodium sorbitol monoborate-pH 5 of Example IV. An equally stable emulsion results' Example VII Substitute triethanol amine .mannitol monoborate-pl-I 8 for the borate of Example IV. An equally stable emulsion results.

' Example VIII Melt together 20 grams of paraffin wax, 1.3 grams of commercial sorbitan monopalmitate, 1.7 grams of 20-polyoxyethylene sorbitan monopalmitate and 0.4 gram of stearic acid. Add to the molten mixture at a temperature of about 60 0., with continuous stirring, a solution of 0.2

while stirring gently. The p 6 Example IX Melt together 20 grams of parafiin wax, 1.3 grams of commercial sorbitan monopalmitate and 1.7 grams oi. 20-polyoxyethy1ene sorbitan monopalmitate. To the molten mixture at a temperature of about 0. add with continuous stirring, a solution of 0.6 gram sodium sorbitol monoborate-pH 7 in 76.4 grams of water, also at about 60 C. Cool the resulting emulsion to room temperature with gentle stirring. The emulsion shows markedly improved stability to shaking when compared with emulsions made in the absence of a borate compound.

Example X Melt togteher 40 grams of parafiin scale wax, 5 grams of sorbitan monostearate, 9 grams of 20- polyoxyethylene sorbitan monostearate, and 0.5 gram stearioacid. Separately prepare a solution of 0.25 grani'pf sodium sorbitol monoboratepH 7 in 45.25 grams of Water and bring the molten mixture and the aqueous solution to temperatures between 60 and 100 C. With continuous agitation add the aqueous solution to the molten wax mixture in a slow stream. Continue gentle agitation as the resulting emulsion cools to room temperature. The resulting concentrated emulsion is a creamy fluid, stable against separation of wax agglomerates on shaking and amenable to dilution to any desired extent with soft or hard Water to form stable dilute emulsions.

Example XI Melt together 20 grams of parailin scale wax 0.9 gram of sorbitan monopalmitate, 1.1 grams of zo-polyoxyethylene sorbitan monopalmitate, and 0.2 gram of stearic acid. Separately prepare a solution of 0.1 gram of sodium sorbitol monoboratepH 7, in 77.7 grams of water. Bring the melt and the solution to temperatures between 60 and 100 C., and add the solution in a slow stream to the molten wax mixture while stirring constantly. Continue gentle agitation while the formed emulsion cools to room temperature. The resulting emulsion is relatively stable to storage and dilution, and shows marked improvement over a companion emulsion made without the addition of borate and stearic acid in respect to agglomeration and separation ofwax upon shaking.

The above examples suffice to illustrate the invention amply, and multiplication of the number of examples illustrating in detail the use of the stabilizing agents with other wax emulsifiers taught in the Gritfin patent will be avoided. Other specific emulsifier combinations which may be employed with the newly disclosed borate stabilizers of the present invention are presented in tabular form below:

Example A Type Emulsifier Parts B Type Emulslfier Parts XII Snrbitan mononaphth- 3. 5 20-POE'manniton mono- I 3. 6 onate palm! te a, XIII..-" Sorbitan mono1aurate... l2 2OI-POE sorbitan monol9 aura XIV Glycerol monopalmitate" 3. 5 20-POE mannitan monoi palmitate 8. 5 XV. Mannltan mono-oleate 3. l2-POE mannitan monooleate. 11. 25

"POE-polyoxyethyleno.

76.4 grams of water,- also at about 60 C. Cool the resulting emulsion to room temperature with gentle stirring.

ethylene groups. Thus .faoe-polyoxyethylene sorbitan monopalmitate is to be. understood as .referring to the polyoxy'eth'ylene ether of sorb'itan monopalmitatecontaininganaverage 0120 oxyethylene groups per mol.

Theaiboveexamples are illustrative only, and notLdefinitive of thelimits of the'invention. Variations therefrom which come within the scope of the'invention will be; obvious to those'skille'd" in -'th e art.

Emulsifi'alble wax compositionsicontaining' "the stabilized. emulsifier hereinbefore described usefully containirom' 10%"to' 30% of said emulsifier and from 70% to 90%""paraflin' wax; or the like.

Emulsions which come-within the purview of the patent may vary in concentration over a wide 'range. :aA-star as 'is .known'they'xmay be diluted -almost'idnfinitely with water although there is flittlenpracticalmse" for paraitfinemulsions conata'i'nin'g lessxthanaabout 5%. .p-araffin'wax and'the invention :primarily concerned with: emulsions :containing:upwards from" this amount. In most *fields'pfrapplication :emulsionsi containing from about 40% ".to about parafiimwax are-.most useful. and it sis-tinthis range of concentrations thatuthe: preferred compositions llie. Of nearly sequal riinptoittance; however; are concentrated; or stock, :emulsions 'which' containv still higher pro- .pnr-tionsamf rparafiin'uand which' may be diluted with? either harder-soft water to form emulsions m'ore's'suited to ultimate application. The improved emulsifiers of the. \present "invention. are particularly well adapted to stabilizing such concentrated emulsions against the agglomeration and separation; of wax particlesand emulsions containing as \muchas- 50%. of combined .parafiin andremulsifienare within the-purview of the in-- vention. the emulsions the proportion of paraffin wax to emulsifier; falls within the same 'range as in theemulsifiable wax compositions, .na-melybetween thelimitsoi from 10% to of the emulsifierand from-90% to 70%paraifinwax.

=.Theemulsions of the-present inventionareusetulin-anycflth known applications of paraflin emulsions. .Among. suchuses maybe mentioned the water-proofing oftextiles or of :porous woods, the-wax coating of paper,- chip board;.and thelike. Such emulsions -.-comprise particularly "useful means of introducing emulsified wax into .'.fluid dispersions with-other ingredients as for. example in combined fluid starch-wax dispersions. as laun- .dryaids.

What claimed-is:

lsiAn emulsifier composition comprising (a) -a-mixture of. lipophilic partial vester .ofa =10ng chain atty acidand a .hydrophiliapolyhydroxylic organic compound,= a highly hydrophiliehtldroxypolyoxyethylene ether of a lipophilic partial ester .ofialong chain fatty acid and a hydrophilic polyhydroxylic organic compound, said vhydroxypolyoxythylene ether containing at least 10 oxy'ethylenegroups; said partial ester and said hydroxyp'olyoxyethylene ether being presentinthe mixture in such proportions that the ratio of oxyethylene groups in said hydroxypolyoxyethylene ether .to' the total ester groups (both in the free-ester and in the-.hydroxypolyoxyethylene etherl in. the range of from; about. 1.5 to 9.0.and (b) from about 2.3% to about 25%v by-weight, based on the weight of the said naixture, of -a hexitol .monoborate .the pH of which has been adjusted to a value between 4.5 to 9.0 by replacement of acid hydrogen of. the said monoborate with a'monovalent cation other "than hydrogen.

An emulsifiercomposition consisting essenslung: chain iatty acid an? amount mot; greater than 2.5 times. the weight. ofi said hexitoltmonoA borate wherein:

of the -:compositio1bof claim; l-aandw a solid the sum of. the weights 'Ofm'Said borate and said fatty-aoidaris no rnore;=than fi0% of the weight of said mixture ((1.)

3. An emulsifier "composition as in claim 2 wherein the said hexitol. monoborate sodium sorbitol monobora'te-r-pH 7, and said solidj'iatty acid .is stearic. .acid.

4.. An emulsifier composition as in claim .2 .wherein the said =lipo'philic partial ester. is. a. ,partial ester of. a polyhydroxylic-cyclic inner etheroi .Lhexitol and .a fatty acid of atdeast'12- carbon atoms, and wherein the 'said 'hydroxypolyoxyethylene .ether is the hydroxypolyoxy'ethylene ether-or a partial ester-of .a polyhydroxylic cyclic inner ether of a hexit'ol and a fattyacidof at least 12 carbon-atoms, saidether containing'.from '10 to 30 oxyethylene groups per mol.

5. An emulsifier. composition consisting of (a) a mixture of'from'40 to Super cent of sorbitan monopalmitate and from 60 tci'50 per cent of'20- polyoxyethylene sorbitan ""monopalmitate; (b) from- 6% to 1'8 basedon theuveight otsaid-mixture, "of sodium sorbital monoboratepI-I l7; and (cf-twice as muchz'stearic acid as said sodium sorbitol monobor'ate.

. 6.'An emulsifier-composition consisting'rof ta.) a mixture of'ir'om' 40 $0 50 perz c'ent of' sorbitan ylene sorbitan monostearate; '(b) .i-roml'fiz-qo to 18%, based on the weight of saidz'mixturepof sodium sorbitol monoborate pH '7; and (c). twice .as"muchstea'ric acid: as said sodium sorbitol composition of claim 5.

11. An aqueous emulsion of parafiln wax, emulsified and stabilized with the emulsifier composition ofclaim? 1.

312. An aqueous: emulsion of 'paramn 'wax, emulsified and stabilized with the emulsifier-composition of claim=2.

.13.. An aqueous emulsion ofiparaflln wax,..emuls'ified and stabilized with the emulsifier. composition of claim 4.

14. An aqueous emulsion of paraflin wax',"emulsified and stabilized with the emuls'ifiercompos'ition of claim 5.

References Cited in the. file of this patent UNITED STATES PATENTS OTHER REFERENCES .Bennett; Commercial Waxes, 1944, page 486,

v '539' and 540.

.Atlas Powder Co., Surface. Active .Agents, Wilmington, Del; page 40.,

:Atlas: Surface Activ jngerits" (1948), page 26and'2'7.

37, Table I between pages 

1. AN EMULSIFIER COMPOSITION COMPRISING (A) A MIXTURE OF LIPOPHILIC PARTIAL ESTER OF A LONG CHAIN FATTY ACID AND HYDROPHILLIC POLYHYDROXYLIC ORGANIC COMPOUND, A HIGHLY HYDROPHILLIC HYDROXYPOLYOXYETHYLENE ETHER OF A LIPOPHILIC PARTIAL ESTER OF A LONG CHAIN FATTY ACID AND A HYDROPHILIC POLYHYDROXYLIC ORGAINC COMPOUND, SAID HYDROXYPOLYOXYETHYLENE ETHER CONTAINING AT LEAST 10 OXYETHYLENE GROUPS; SAID PARTIAL ESTER AND SAID HYDROXYPOLYOXYETHYLENE ETHER BEING PRESENT IN THE MIXTURE IN SUCH PROPORTIONS THAT THE RATIO OF OXYETHYLENE GROUPS IN SAID HYDROXYPOLYOXYETHYLENE ETHER TO THE TOTAL ESTER GROUPS (BOTH IN THE FREE ESTER AND IN THE HYDROXYPOLYOXYETHYLENE ETHER) IS IN THE RANGE OF FROM ABOUT 1.5 TO 9.0 AND (B) FROM ABOUT 3% TO ABOUT 25% BY WEIGHT, BASED ON THE WEIGHT OF THE SAID MIXTURE, OF A HEXITOL MONOBORATE THE PH OF WHICH HAS BEEN ADJUSTED TO A VALUE BETWEEN 4.5 TO 9.0 BY REPLACEMENT OF ACID HYDROGEN OF THE SAID MONOBORATE WITH A MONOVALENT CATION OTHER THAN HYDROGEN.
 7. AN EMULSIFIABLE WAX CONSISTING ESSENTIALLY OF FROM 70% TO 90% PARAFFIN WAX AND FROM 30% TO 10% OF THE EMULSIFIER COMPOSITION OF CLAIM
 1. 